In a conventional leading or trailing arm trailer suspension, a leading or trailer arm, respectively, extends from the trailer frame for connection with the trailer axle. The arm is pivotally connected at one end to the trailer frame and is also connected at a second end to the trailer axle. The arm may extend over or under the trailer axle and supports an air spring thereon.
In one known trailer suspension, to lock the trailer at a predetermined positional height and to prevent the trailer from moving during loading and/or unloading, the trailer suspension includes a locking mechanism. In one embodiment, the locking mechanism utilizes the weight of the trailer to engage and lock the trailer to a predetermined height against the dock. After the trailer is loaded or unloaded, the air springs are activated such that the air springs are inflated to lift the trailer up and release the dock lock. However, even though the air springs may inflate to full pressure, the dock lock may stick such that the weight of the trailer may keep the dock lock engaged. Accordingly, as the trailer pulls away from the dock and goes over a bump, the trailer rises, taking the weight off the locking mechanism and disengaging it such that the locking mechanism slams down on travel limit stops, oftentimes causing damage to the trailer suspension.
In addition, welded connections on the trailer axles may be weakened and often fail due to the sudden weight crashing down. Further, the stress placed on the welded connections often extends to the axle itself, resulting in a weakening or failure of the axle.
Therefore, there is a need for an improved suspension system that will minimize or eliminate one or more of the above-mentioned deficiencies.